1. Field of the Invention
The present invention relates to a fixing device for, after an image is formed on a recording medium from a thermally meltable recording material, fixing the image onto the recording medium by heating the recording medium.
2. Description of the Related Art
Conventionally, there have been image forming devices such as copy machines, printers, and facsimile machines that form images on a recording medium. One type of image forming device impinges a thermally meltable recording material onto a recording medium to form an image on the recording medium from the thermally meltable recording material. This type of image forming device normally includes a fixing device that heats the recording medium to melt or soften the recording material on the recording medium and to fix the recording material onto the recording medium. For example, an electrophotographic image forming device, such as a laser printer, uses toner as the thermally meltable recording material. The fixing device heats the recording medium to melt or soften the toner melt and fix the toner onto the recording medium.
Japanese Patent-Application Publication (Kokai) No. HEI-8-314309 discloses a fixing unit used in this type of image forming device. The fixing unit includes a thermal roller and a pressing roller. The thermal roller is formed from a metal tube and a sheet-shaped heating element fixed to the inner surface of the metal tube. The heating element heats up the metal tube. The heat from the metal tube is applied to a recording medium sandwiched between the thermal roller and the pressing roller. The recording medium is heated up as a result.
In order to supply power to the sheet-shaped thermal body, even though it rotates with rotation of the thermal roller, sliding contact mechanisms for supplying power to the sheet-shaped thermal body are provided at either end of the thermal roller. Each sliding contact mechanism includes a rotational electrode member that rotates integrally with the thermal roller, and a stationary electrode member disposed in contact with the rotational electrode member. The rotational electrode member is formed from a metal tube mounted on the corresponding end of the thermal roller. The stationary electrode member is formed from a metal rib supported on a casing of the image forming device, in contact with the outer peripheral surface of the corresponding metal tube. With this configuration, electrical connection between the rotational and stationary electrode members can be maintained even while the thermal roller is rotating.